1. Field of the Invention
The present invention generally relates to ampul processing machines and, more particularly, to arrangements for and methods of improving the ampul handling capacity of such machines.
2. Description of the Prior Art
It has been proposed in the art of ampul filling and sealing machines to fill glass ampuls with metered amounts of liquid medicament or the like, and to seal such filled ampuls by playing a flame around the middles of the necks of such ampuls, generally above a ceramic bead or ring disposed around the base of the neck of each ampul. In use, the ampul neck portion above the bead is snapped off at the ceramic bead, and a hypodermic needle is inserted into the ampul. The plunger of the syringe is operative to draw the medicament into the syringe and, after insertion of the needle into a patient's body, manual movement of the plunger towards the needle forces the medicament into the patient's body.
Known machines which process ampul sizes on the order of 1/2 cubic centimeter to 20 cubic centimeters have a handling capacity or throughput of approximately 120 ampuls per minute on a single line. In order to increase the throughput, it has also been proposed to increase the number of ampul lines. However, duplication of parts is an expensive expedient.
In order to keep the throughput high, it is desirable to quickly guide a relatively large number of ampuls through an infeed guide chute which converges downstream of ampul flow. However, ampuls often jam and bridge across the infeed guide chute, thereby blocking further ampul advancement.
In order to prevent such jamming, air-type or mechanical-type vibrators were used. However, air-type vibrators are objectionable because they are noisy and use non-sterile air. Mechanical-type vibrators are likewise noisy and have not proven altogether satisfactory in use.
It has further been proposed to intermittently advance a chain conveyor having ampul-receiving pockets past the filling and sealing stations of the machine. During a cycle of one second, for example, the chain conveyor takes 1/4 second to advance and remains stationary for 3/4 second. It is known to feed ampuls one at a time through a stationary infeed chute to the pockets of the chain conveyor.
In order to increase the throughput of the machine, it has also been proposed to feed two ampuls during the 1/4 second advancement time period. The first ampul is shot into one pocket while the chain is advancing, and the second ampul is shot into another pocket just as the chain stops. This proposal has the drawbacks of limited speed and ampul breakage, particularly of the first ampul.
It has further been proposed to feed four ampuls during the 1/4 second advancement time period. Now the first, second and third ampuls must be shot into three successive pockets while the chain is advancing, and the fourth ampul must be shot into the last pocket just as the chain stops. The drawbacks of limited speed and ampul breakage are magnified with this proposal. It will be noted that each ampul only has 1/16 of a second to be fed into a moving pocket. The last ampul frequently does not have sufficient time to be registered into its pocket.
It has still further been proposed to discharge ampuls one at a time from the chain conveyor during the 1/4 second advancement time period. An inclined jog or tongued guide is interposed transversely of the path of ampul travel. The chain conveyor advances the ampuls and deposits them against the jog, whereupon the jog diverts the ampuls away from the path. However, this proposal has the drawback that each ampul slams into the jog, thereby causing ampul breakage.
Another prior art proposal discharges ampuls two at a time against the jog. It will be recognized that propelling two ampuls against the jog during a 1/4 second advancement time period greatly magnifies the problem of ampul breakage. Furthermore, it is known to drive the chain conveyor by a Geneva drive mechanism whose movement characteristic starts from zero speed, accelerates rapidly to a maximum value midway during the advancement stroke, and then decelerates rapidly towards zero. Thus, the first ampul is thrown against the jog at approximately maximum acceleration, and the second ampul also slams against the first ampul at high speed. Of course, the problem of ampul breakage increases for the discharge of more than two ampuls because the conveyor chain has to work faster.